This invention relates to heading instruments in general and more particularly to a low cost instrument containing a visual display of heading for tanks.
The present low cost technique for providing heading information in tanks requires a magnetic sensor to initialize the system and a directional gyroscope for maintaining the alignment. In a system of this nature the visual read out of heading information is an indicator card mounted on the control panel which is servoed to a synchro on the directional gyroscope.
The primary disadvantage of this system is that it uses a magnetic sensor for alignment which can be affected by large iron or steel structures. In tanks for example, a turret would have to be in a fixed position during alignment in order to avoid degrading the accuracy of the system. Also the proximity of other armored vehicles at this time can introduce errors in the heading.
Another disadvantage of this system is that the components take up a considerable amount of space, something that is at a premium in tanks.
Some expensive devices have utilized a gyrocompassing function with the use of accelerometers and bubbles which in addition of increasing the cost have increased the overall complexity of the system.
It is an object of this invention to provide a low cost heading indicator which is insensitive to weak magnetic fields of ferrous structures proximate to the device.
It is another object of the invention to provide a low cost heading indicator that is smaller in volume than the presently used device.
Another object of the invention is to combine the functions of a gyrocompass and a directional gyro in a single device without the need for accelerometers or bubbles.
Another object of this invention is to provide a system that aligns itself to true North within 5 minutes, that is insensitive to magnetic anomalies and that can then be switched to a directional gyroscope mode to give heading indications.
It is another object of the invention to provide a low cost heading indicator with a direct gyro readout providing heading information.